Tuyere for slag-blowing furnaces



Sept. 24, 1929- A. LAIST 1,729,075

- TUYERE FOR S LAG BLOWING FURNACES Fild Aug. 4, 1928 2 Sheets-Sheet 1Sept. 24, 1929. AL LAIST TUYERE FOR S LAG BLQWING FURNACES Filed Aug. 4,1928 2 Sheets-Sheet 2 awuwtoz v l-EX LA/J 7':

Patented Sept. 24, 1929 UNITED STATES PATENT OFFICE ALEX LAIST, OFHELENA, MONTANA, ASSIGNOR TO ANAGONDA COPPER MINING COM-.

PANY, A CORPORATION OF MONTANA TUYERE FOR SLAG-BLOWING FURNACESApplication filed August 4, 1928.

In tuyercs for slag-blowing furnaces and similar apparatus, a stream ofair is caused to flow in a horizontal direction immediately at.orpr1orto,1ts passage through the tuyere and 5 a downwardly flowingstream of pulverized fuel, suspended in air, is caused to enter the airstream at an angle. In tuyeres heretofore used, the impinging of thestream of powdered coal on the air stream deflected the re- 10 sultantstream downwardly from the horizontal, and thus caused the mixed streamand the particles of suspended fuel to strike the wall of the tuyere.The striking of the suspended particles on the wall of the tuyere causeda 15 rapid erosion or wearing away of the tuyere and, therefore,necessitated frequent repairs or replacement.

This advantage is obviated in my present invention which provides atuyere and an air 2 and fuel supply means that avoids any impingement offuel, or other particles, on the wall of the tuyere and thus preservesthe tuyere against erosion, and that enables the mixed air and fuelstream to flow substantially horizontally or parallel to the tuyerepassages.

The various features of the invent-ion are illustrated in theaccompanying drawings, in which 3 Fig. 1 is a plan View of a tuyereembodying a preferred form of the invention.

Fig. 2 is a vertical sectional view of the tuyere taken on the line 22of Fig. 1.

Fig. 3 is a vertical section taken on the line 3-3 of Fig. 2, and

Fig. 4: is an end view of the tuyere In the type of tuyere to which mypresent invention is applied air under pressure is supplied downwardlythrough a vertical pipe to a casting 11 into which the pipe is threaded.The air is received in a chamber 12 which is formed in the outer end ofthe casting and is closed by an end plate 13. From the chamber 12 theair flows through a passageway let into a mixing chamber 15 of asomewhat rounded or globular shape. In the chamber 15 the air is joinedby'a stream of fuel suspended in air and then passes through an outletpassage 16 into a tuyere Serial No. 297,451.

pipe 17 that leads through the wall of the converter or furnace.

A stream of powdered fuel suspended in a carrying current of air, underpressure, is supplied downwardly through a pipe 18 positioned betweenthe air pipe 10 and the wall 19 of the converter. From the pipe 18 theair is received in an expansion chamber 20 formed 1n the castingllimmediately aboveand openin g downwardly into the mixing chamber. 15.The expansion chamber 20 is of considerably larger horizontal crosssection than is the fuel admission pipe 18 and also increases in crosssectional area downwardly towards the mixing chamber 15. It ispreferably of rectangular cross section having parallel walls 21 and 22at right angles to the horizontal direction of flow of the air throughthe mixing chamber 15, and having a pair of diverging walls 23 and 24that meet the outermost part of the mixing chamber 15 at approximately athe expansion chamber 20, the cross-sectional area of the passage forthe air and its suspended fuel is increased and the velocity iscorrespondingly reduced. As the air and fuel pass downwardly through thechamber 20, the cross-sectional area widens to the diameter of thechamber 15 and the air and suspended fuel, therefore, enter the mixingchamber 15 uniformly distributed across the path of the air passinghorizontally therethrough, and at a velocity insufficient to materiallydeflect the stream of air. The particles of suspended fuel are,therefore, carried horizontally by the passing air without impinging, toany destructive extent, upon the side walls of the tuyere.

The tuyere may be provided with the usual slag-overflow pipe 25 securedin an opening at the lower part of the chamber 15 and sealed therefromby means of a fusible disc 26 held in place by a bushing 27. The endplate 13 may also be provided with an inlet check valve 28 of usualconstruction.

As changes of construction could be made within the scope of myinvention, it is in tended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

In previous applications of Garred No. 181,979 filed April 8, 1927, andof myself No. 284,462 filed June 11, 1928, there are described apparatusfor recovering zinc and other metals from slags or the like, by blowingthrough the molten material a mixture of air and finely divided coal orotherfuel. The present improvement is designed par-,

ticularly for use in such blowing operations,

though it may be used with advantage wherever similar conditions exist.

Having now described my invention, what lclaim as new and desire tosecure by Letters Patent is 2.

1. A tuyere of the type described which comprises a horizontal airpassage, and a fuel passage entering said air passage at an angle. saidfuel passage being enlarged adjacent its entrance to said air passage toreduce the velocity of fuel prior to its on- 'trance to said airpassage.

2. A tuyere of the type described which comprises a horizontal air passae, and a fuel passage entering said air passage at a' right angle, saidfuel passage being enlarged adjacent its entrance to said air passage toreduce the. velocity of fuel passing therethrough prior to its entranceto said air passage.

3. A tuyere of the type described which comprlses an a1r passage, a fuelpassage opening into said a1r passage at an angle,

* the cross sectional area of said fuel passage increasing towards saidair passage.

4. A tuyere of the type described which comprises a casting having anair passage therethrough, a fuel passage opening at right angles to saidair passage and having parallel front and back walls at a right angle tothe direction of flow through said air passage, and side walls divergingtowards said air passage.

In witness whereof, I have hereunto signed my name.

ALEX LAIST.

